System and method for generating and verifying a self-authenticating document

ABSTRACT

Described are a system and method for verifying a self-authenticating document. First, an image is obtained of at least a predetermined portion of the document. Then, the image is divided into a predetermined number of pixel groups, each pixel group including a plurality of pixels and pixel characteristic data for each pixel is determined. A pixel group classification data for each pixel group is determined as a function of the pixel characteristics data. Based on the pixel group classification data and a location of the corresponding pixel group in the image, a characteristic digital data “CDD” for the image is generated. The CDD is added to the document. Upon a request for verification of the document, the CDD is extracted from the document. Then, a further CDD based on the image is generated. The document is verified only if the CDD is substantially identical to the further CDD.

PRIORITY CLAIM

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/358,848 filed Feb. 22, 2002 and entitled “SecureAssociation of Photographs with Digital Information”. This applicationis expressly incorporated herein, in its entirety, by reference.

BACKGROUND INFORMATION

Recently, there has been resurgence of interest in creating the nextgeneration of identification (“ID”) cards that provide greater securitythen previously issued ID cards. The new ID cards are expected toprovide at least the following two features with a high degree ofreliability. First, the ID card must be associated with a person whocarries the ID card by providing some verifiable biometric values.Second, there must be an easy way to detect counterfeit or altered IDcards.

One approach is to have a photo on the ID card that may be verified asauthentic. There are several existing technologies that attempt toaddress this issue. One technology allows for the digital watermarkingof the photo by artificially altering predetermined portions of thephoto. The photo is then verified by detecting the existence of thedigital watermark. The digital watermarking technology, however, has adisadvantage that a substituted photo with the same watermarking cannotbe detected.

Another existing technology is utilization of a photo verificationdatabase. However, this technology is costly because it requiresspecialized verification equipment and a communication channel to thephoto verification database. Furthermore, this technology relies on thedatabase being available for a verification procedure at any given time.

There is, therefore, a need for an ID card system that allows for thedetection of an alerted photo. At the same, the system should beindependent of a database (e.g., self-verifying). Furthermore, thesystem should be one that may be implemented with relatively inexpensivehardware, and require only a small amount of data to be stored on the IDcard. The system should also be robust enough to work despite variationsin a verification device's performance and wear and tear on the ID card.

SUMMARY OF THE INVENTION

The present invention relates to a system and method for verifying aself-authenticating document. First, an image is obtained of at least apredetermined portion of the document. Then, the image is divided into apredetermined number of pixel groups, each pixel group including aplurality of pixels and pixel characteristic data for each pixel isdetermined. A pixel group classification data for each pixel group isdetermined as a function of the pixel characteristics data. Based on thepixel group classification data and a location of the correspondingpixel group in the image, a characteristic digital data “CDD” for theimage is generated. The CDD is added to the document.

Upon a request for verification of the document, the CDD is extractedfrom the document. Then, a further CDD based on the image is generated.The document is verified only if the CDD is substantially identical tothe further CDD.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an exemplary system according to the present invention;

FIG. 2 shows an exemplary embodiment of an identification card accordingto the present invention;

FIG. 3 a shows an exemplary embodiment of a photo split into pixelgroups;

FIG. 3 b shows an exemplary embodiment of a pixel group;

FIG. 3 c shows Table A illustrating an exemplary classification schemefor the pixel groups;

FIG. 4 shows an exemplary embodiment of a method for generatingcharacteristic digital data according to the present invention;

FIG. 5 shows an exemplary embodiment of a method for issuing theidentification card; and

FIG. 6 shows an exemplary embodiment of a method for verifying acustomer using the identification card.

DETAILED DESCRIPTION

The present invention relates to a system and method for generating andverifying a self-authenticating document, and in particular, anidentification card. FIG. 1 shows an exemplary system 1 according to thepresent invention. The system 1 may include an issuer 2, a cardholder 4and a user 6. The issuer 2 may be an entity that performs a backgroundcheck verification procedure to confirm the identity of the cardholder 4and issues an identification (“ID”) card 8 (shown in FIG. 2) to thecardholder 4. The cardholder 4 may be a person or entity whose identityneeds to be securely verified. The user 6 may be an entity (e.g., thepolice, bank, etc.) that requires reliable identification of thecardholder 4.

Upon the user's 6 request for a reliable form of identification, thecardholder 4 may present the ID card 8 issued by the issuer 2. The user6 may then verify the information on the ID card 8 and determine if theID card 8 belongs to the cardholder 4. This may eliminate the need forthe user 6 to perform the background check verification procedure oreven to contact the issuer 2 to verify an identification of thecardholder 4.

FIG. 2 shows an exemplary embodiment of the ID card 8 according to thepresent invention. The ID card 8 may be a driver license issued by alocal Department of Motor Vehicles (“DMV”), a passport issued by theState Department, etc. The ID card 8 may have a front portion 10 and aback portion 20. The front portion 10 may include a photo 12, an IDnumber 14, personal information 16, a signature 18, etc. The frontportion 10 may also include biometric identifiers such as a fingerprint,an iris scan, etc.

The back portion 20 of the ID card 8 may contain certain data stored ina format that may be reliably captured by an ID card scanner/readingarrangement. In the preferred embodiment, the data is stored in atwo-dimensional (“2D”) bar code 30. The data encoded in the 2D bar code30 may include the data shown on the front portion 10. In addition, thedata may include certain information that allows for the verification ofthe ID card 8 (e.g., characteristic digital data “CDD” of the photo 12).The bar code 30 may be combined with another barcode, if any, which maybe already placed on the back portion 20. Those skilled in the art wouldalso understand that the bar code 30 along with any other informationsituated on the back portion 20 may be situated on the front portion 10.

FIG. 3 a shows an exemplary embodiment of a scanned image of the photo12 subdivided into pixel groups to create the CDD (this subdivision isimaginary and is not actually drawn). A center portion of the image maybe split into a regularly-spaced grid of pixel groups 40. For example,the grid may be 16 columns by 24 rows of the pixel groups 40. The numberof the pixel groups 40 may be a function of the ideal size of the CDDand the number of bits needed to classify the pixel group 40. The edgesof the image may contain border area 42 that are not included in thepixel groups 40.

The border area 42 may contain a prearranged pattern. In the preferredembodiment, the pattern includes lines of different and distinctthickness and luminance. These lines allow the scanning arrangement toself-calibrate (i) alignment and (ii) response to luminance whenscanning the ID card 8. This prearranged pattern may also conveyinformation about the size of the pixel group grid, the location ofcolumns and rows within the grid, etc.

FIG. 3 b shows an exemplary embodiment of the pixel group 40 subdividedinto a plurality of pixels. For example, the pixel group 40 may be asquare shape and contain a grid of 18 by 18 pixels 46. The size of thepixel group 40 may be a function of the size of the photo 12, the numberof pixel groups 40 and a density of (dots per inch) of printed images.

Certain factors may be considered when determining the number of pixelgroups 40 as it affects the size of the pixel group 40. For example,slight misalignments in scanning may have less of an effect when thepixel group 40 is large. On the other hand, if the size of the pixelgroup 40 increases, then the CDDs of two different photos may becomeless unique. Therefore, optimization of the number of the pixel groups40 for a particular application may be necessary.

FIG. 4 shows an exemplary embodiment of a method according to thepresent invention. In Step 100, the photo 12 is scanned, using thearrangement, to generate a digital image representation of the photo 12.The arrangement processes the digital representation by dividing it intoa predetermined number of the pixel groups 40. A number of pixels 46 ofthe pixel group 40 depends on a resolution of the arrangement. Thearrangement may have a resolution of 300 pixels per inch, or 135,000pixels in 1 inch by 1.5 inches, which may be a typical size for thephoto 12. Some arrangements may represent each pixel 46 as an eight-bitgray value and other arrangement may represent each pixel with three8-bit numbers representing the amount of red, green and blue for a totalof 24 bits.

In Step 110, a subset of the characteristic data for each pixel 46 isextracted. For example, if the image is a color image, using the valuesred, green and blue, a characteristic brightness or luminance of thepixel 46 may be determined by the following equation:luminance=0.3×red+0.59×green+0.11×blue.However, if the image is a monochrome gray scale, then thecharacteristic data of pixels is the digitized value for that pixel.

One skilled in the art understands that other characteristic values ofthe pixel 46 may be used (e.g., the value of a single color).Furthermore, one skilled in the art understands that the number of bitsrepresenting the values depends upon the sophistication of thearrangement.

In Step 120, each pixel group 40 is classified into a number ofpredetermined subsets. The number of subsets may be determined as afunction of the number of bits that may be used to represent the pixelgroup 40. In the exemplary embodiment, the pixel group 40 may beallocated with two bits. In such case, as illustrated in Table A of FIG.3 c, the pixel group 40 may be classified into four subsets: 0, 1, 2, 3.Those skilled in the art will understand that three or more bits perpixel group 40 may be utilized. An average pixel group characteristicdata for a particular pixel group is determined as an average of allpixel characteristic data in that pixel group 40. If the allowed rangeof individual pixel value is between 0 and 255 and the average pixelgroup classification is, for example, between 0 and 63, then the pixelgroup 40 is given a classification of 0.

In Step 130, the CDD is determined as a function of the pixelclassification characteristic data and location of the correspondingpixel group 40 in the photo 12. For example, the CDD may be stored as abit string where left-to-right row-by-row pixel classification datastarts from an uppermost row of the photo 12.

FIG. 5 shows an exemplary method according to the present invention forgenerating the ID card 8. Initially, the issuer 2 obtains necessaryinformation about cardholder 4 (e.g., data shown on the front portion10). In Step 140, the issuer 2 generates the CDD as a function of thephoto 12 by utilizing the method described above and shown in FIG. 4.

In Step 150, the issuer 2 generates the ID card 8 which includes theCDD. In particular, the issuer 2 may combine the generated CDD withother data (e.g., the ID number 14, the personal information 16, etc.)to create a single data file. The issuer 2 may then digitally secure thefile using one of conventional digital signature technologies (e.g., RSAdigital signature and Digital Signature Algorithm (DSA), etc.).

In the exemplary embodiment of the present invention, the file may bestored in the form of the 2D bar code 30. Those skilled in the artunderstand that the file with the CDD may be stored on the ID card 8utilizing other data storage formats (e.g., an embedded chip in a“smart” card). Once the ID card 8 is generated, it is forwarded to thecardholder 4.

FIG. 6 shows an exemplary embodiment of a method according to thepresent invention for verifying the identity of the cardholder 4 usingthe ID card 8. In particular, the cardholder 4 needs to be verified forthe user 6. The cardholder 4 presents the ID card 8 to the user 6. InStep 160, the user 6 scans/reads the CDD which is stored in the ID card8 using the arrangement. The arrangement decodes the file stored on theID card 8, decrypts it (if the file was originally encrypted) and thenextracts the stored CDD.

In Step 170, a further CDD is generated from the photo 12. This step isperformed utilizing the method described above and shown in FIG. 4. Inparticular, the arrangement, as previously mentioned, scans the photo 12and utilizes the border pixel pattern to self-calibrate and ensuresreliable results. The further CDD is generated as described above.

In Step 180, the stored CDD and the further CDD are compared to verifythe authenticity of the photo 12. Due to imperfections in the scanningprocess and wear and tear on the ID card 8, a perfect match between theCDDs may not always be expected. The user 6 may, therefore, set apredetermined threshold of similarity between the CDDs for verificationof the cardholder 4. For example, the user 6 may decide the CDDs must besubstantially similar (e.g., above 80%); but in particular cases, theymust be 96% identical, etc.

The arrangement may employ a matching algorithm that applies more weightto severe mismatches (e.g., a difference of two levels of luminance is agraver mismatch than one level luminance). The algorithm may also attacha greater weight to the matches and mismatches toward the center of thephoto 12 or where there is likely to exist more unique features withinthe photo 12. In addition, finding two-dimensional matches or mismatchesin luminance changes across a boundary that extends along multiplegroups (e.g., changes of luminance between groups) may be stronglyweighted by the algorithm.

There are many modifications to the present invention that will beapparent to those skilled in the art without departing from the teachingof the present invention. The embodiments disclosed herein are forillustrative purposes only and are not intended to describe the boundsof the present invention which is to be limited only by the scope of theclaims appended hereto.

1. A method for verifying a self-authenticating document, comprising thesteps of: (a) obtaining an image of at least a predetermined portion ofthe document; (b) dividing the image into a predetermined number ofpixel groups, each pixel group including a plurality of pixels; (c)determining pixel characteristic data for each pixel; (d) determining apixel group classification data for each pixel group as a function ofthe pixel characteristics data of at least one pixel in the pixel group;(e) generating a characteristic digital data “CDD” for the image as afunction of the pixel group classification data and a location of thecorresponding pixel group in the image; (f) adding the CDD to thedocument; (g) upon a request for verification of the document,extracting the CDD from the document; (h) repeating steps (a)–(e) togenerate a further CDD based on the image; and (i) verifying thedocument if the CDD is substantially identical to the further CDD. 2.The method of claim 1, further comprising the step of: before step (f),digitally securing the CDD using a predetermined encryption system. 3.The method of claim 2, further comprising the step of: before step (i),verifying the digitally secured CDD.
 4. The method of claim 1, whereinthe step (f) includes the following substeps: generating a barcode whichincludes the CDD; and securely attaching the barcode to the document. 5.The method of claim 4, wherein the barcode is a two-dimensional barcode.6. The method of claim 1, wherein steps (a) & (h) are performed using anarrangement which includes a digital scanner.
 7. The method of claim 1,wherein step (b) includes the following substeps: dividing the imageinto a center portion and a border portion; and dividing the centerportion into the predetermined number of pixel groups, wherein theborder portion is capable of containing data relating to the centerportion.
 8. The method of claim 1, wherein the number of pixel groups isdetermined as a function of at least one of a size of the CDD and a sizeof the pixel group classification data.
 9. The method of claim 1,wherein a size of each pixel group is determined as a function of atleast one of a size of the image, the number of pixel groups and adensity of the image.
 10. The method of claim 1, wherein, if the imageis a monochrome gray image, the characteristic data of each pixel is adigitized value of the corresponding pixel.
 11. The method of claim 1,wherein, if the image is a color image, the characteristic data of eachpixel is determined as a function of a digitized red value, adigitalized blue value and a digitized green value of the correspondingpixel.
 12. The method of claim 1, wherein the pixel group classificationdata is an average value of each pixel characteristic data.
 13. A methodfor generating a self-authenticating document, comprising the steps of:obtaining an image of at least a predetermined portion of the document;dividing the image into a predetermined number of pixel groups, eachpixel group including a plurality of pixels; determining pixelcharacteristic data for each pixel; determining a pixel groupclassification data for each pixel group as a function of the pixelcharacteristics data of at least one pixel in the pixel group;generating a characteristic digital data “CDD” for the image as afunction of the pixel group classification data and a location of thecorresponding pixel group in the image; and adding the CDD to thedocument.
 14. A system for verifying a self-authenticating document,comprising: a first arrangement including a processor, a digital scannerand an output device, the first arrangement obtaining an image of atleast a predetermined portion of the document using the digital scanner,the processor dividing the image into a predetermined number of pixelgroups, each pixel group including a plurality of pixels, the processordetermining pixel characteristic data for each pixel, the processordetermining a pixel group classification data for each pixel group as afunction of the pixel characteristics data of at least one pixel in thepixel group, the processor generating a characteristic digital data“CDD” for the image as a function of the pixel group classification dataand a location of the corresponding pixel group in the image, the outputdevice adding the CDD to the document; and a second arrangementincluding a processor, a digital scanner and an input device, wherein,upon a request for verification of the document, the input deviceextracts the CDD from the document, the processor generating a furtherCDD based on the image, the second arrangement verifying the document ifthe CDD is substantially identical to the further CDD.
 15. The system ofclaim 14, wherein the first arrangement digitally secures the CDD. 16.The system of claim 15, wherein the second arrangement verifies thedigitally secured CDD.
 17. The system of claim 14, wherein the outputdevice is a barcode generator which generates a barcode which includesthe CDD and securely attaches the barcode to the document.
 18. Thesystem of claim 17, wherein the input device is a barcode reader whichreads the barcode and extracts the CDD from the barcode.
 19. The systemof claim 17, wherein the barcode is a two-dimensional barcode.
 20. Anarrangement for generating a self-authenticating document, comprising: adigital scanner the digital scanner obtaining an image of at least apredetermined portion of the document; a processor dividing the imageinto a predetermined number of pixel groups, each pixel group includinga plurality of pixels, the processor determining pixel characteristicdata for each pixel, the processor determining a pixel groupclassification data for each pixel group as a function of the pixelcharacteristics data of at least one pixel in the pixel group, theprocessor generating a characteristic digital data “CDD” for the imageas a function of the pixel group classification data and a location ofthe corresponding pixel group in the image; and an output device addingthe CDD to the document.